Integrated fuel processor for rapid start and operational control

Abstract

A fuel processor for rapid start and operational control. The fuel processor includes a reformer, a shift reactor, and a preferential oxidation reactor for deriving hydrogen for use in creating electricity in a plurality of H 2 —O 2 fuel cells. A heating and cooling mechanism is coupled to at least the shift reactor for controlling the critical temperature operation of the shift reactor without the need for a separate cooling loop. This heating and cooling mechanism produces or removes thermal energy as a product of the temperature of the combustion of air and fuel. Anode effluent and cathode effluent or air are used to control the temperature output of the heating mechanism. A vaporizer is provided that heats the PrOx reactor to operating temperature.

1. A method for controlling a reforming fuel cell system, the method comprising the steps of:
 generating a H 2 -containing reformate in a reformer, said reformate having a level of carbon monoxide; 
 passing said reformate through a first reactor to reduce said level of carbon monoxide in said reformate; 
 reacting said reformate with oxygen in a fuel cell stack to create electrical energy and an anode effluent; 
 inputting said anode effluent into a combustor to generate a exhaust stream; 
 adjustably inputting an oxidant into said combustor to control the temperature of said exhaust stream; and 
 transferring heat from said exhaust stream directly to said first reactor such that the temperature of said first reactor is maintained within an operating range. 
 
     
     
       2. The method of  claim 1  wherein the heat generated in said first reactor is balanced with the heat transferred to said first reactor from said exhaust stream to maintain said the temperature of said first reactor within said operating range. 
     
     
       3. The method of  claim 1  wherein said fuel cell stack creates a cathode effluent which is adjustably input into said combustor as said oxidant. 
     
     
       4. The method of  claim 1  further comprising the step of controlling the temperature of said exhaust stream by extracting heat from said exhaust stream prior to transferring said heat to said first reactor. 
     
     
       5. The method of  claim 4  wherein the step of extracting heat from said exhaust stream comprises introducing a cooling spray stream into said exhaust stream. 
     
     
       6. The method of  claim 5  further comprising the step of adjusting the rate of said cooling spray stream as a function of the amount of said anode effluent produced. 
     
     
       7. The method of  claim 4  wherein the step of extracting heat from said exhaust stream comprises passing said exhaust stream through a vaporizer to produce a steam stream. 
     
     
       8. The method of  claim 7  further comprising the step of inputting said steam stream through a second reactor disposed between said first reactor and said fuel cell stack. 
     
     
       9. The method of  claim 8  further comprising the step of adjusting a rate of steam stream through said second reactor such that the temperature of said second reactor is maintained within a second operating range. 
     
     
       10. In a fuel processing system of the type having a reformer breaking down a hydrocarbon fuel into an H 2  containing reformate stream and first and second rectors disposed downstream of the reformer for reducing the level of carbon monoxide in the reformate stream, a method of rapidly starting the fuel processing system:
 generating a heated gas stream in a heating device; 
 directing said heated gas stream through a first side of a heat exchanger; 
 directing water through a second side of said heat exchanger to produce a steam stream; 
 heating said first reactor with said heated gas stream at a first rate of heating; 
 heating said second reactor with said steam stream at a second rate of heating; and 
 controlling said heating device to adjust said heated gas stream, thereby controlling said first and second rates of heating. 
 
     
     
       11. The method of rapidly starting a fuel processing system of  claim 10 , further comprising the step of injecting water into said heated gas stream to control the temperature of said heated gas stream. 
     
     
       12. The method of rapidly starting a fuel processing system of  claim 10 , further comprising adjusting said heating device as a function of the temperature of at least one of said first and second reactors. 
     
     
       13. The method of rapidly starting a fuel processing system of  claim 10 , further comprising the step of generating a second heated gas stream in a second heating device and directing said second heated gas stream through said reformer to heat said first reactor at a third rate of heating. 
     
     
       14. The method of rapidly starting a fuel processing system of  claim 13 , further comprising the step of heating said reformer with said steam stream. 
     
     
       15. The method of rapidly starting a fuel processing system of  claim 14 , further comprising the steps of directing said reformate stream through a first side of a second heat exchanger and directing said steam stream through a second side of said second heat exchanger. 
     
     
       16. A method for controlling a reforming fuel cell system, the method comprising the steps of:
 generating a H 2 -containing reformate in a reformer, said reformate having a level of carbon monoxide; 
 passing said reformate through a first reactor to reduce said level of carbon monoxide in said reformate; 
 reacting said reformate with oxygen in a fuel cell stack to create electrical energy and an anode effluent; 
 inputting said anode effluent into a combustor to generate a exhaust stream 
 adjustably inputting an oxidant into said combustor based on the temperature of said first reactor to control the temperature of said exhaust stream; and 
 transferring heat from said exhaust stream directly to said first reactor such that the temperature of said first reactor is maintained within an operating range.